Five-0 helps the CIA search for a killer on the island as the third season ends. Meanwhile, Kono goes on the run when she is accused of a murder that she didn't commit; and McGarrett makes a shocking discovery when he visits Wo Fat in prison.

McGarrett and Wo Fat narrowly escape from maximum security as Season 4 begins. Meanwhile, gunmen storm Five-0 headquarters and kidnap Catherine. To rescue her, Steve is forced to break the law and go up against a tough new SWAT commander. Also: Kono and Ad (more…)McGarrett and Wo Fat narrowly escape from maximum security as Season 4 begins. Meanwhile, gunmen storm Five-0 headquarters and kidnap Catherine. To rescue her, Steve is forced to break the law and go up against a tough new SWAT commander. Also: Kono and Adam's secret location in Hong Kong is compromised.